<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
    <script>
        // 找出数组中 元素为10的下标，有则打印该下标，没有则打印-1

        let age = []
        let arr = -1
        // 循环遍历
        while(age.length < 5) {
            let num = +prompt(`请输入第个${age.length + 1}人`)
            if(num >0 && num <100) {
                age.push(num)
            }
        }
        for(let i = 0; i < age.length; i++) {
            if(age[i] === 10) {
                arr = i
                break
            }
        }
        document.write(arr);

    </script>
</body>
</html>